Ahead of the 150th running of the Preakness Stakes, here’s the origin story of the second jewel in horse racing’s Triple Crown. It starts at a dinner party.

This year's Preakness Stakes will go down in history because it's the 150th anniversary of the iconic horse race. It's also the final time the race will be held at Pimlico Race Course. Nine, three-year-old thoroughbreds will compete for the honor of winning the "Middle Jewel" of the Triple Crown.